Michael Holmes

Project title: Worker reproductive parasitism in social bees

During Honours I examined the effects of reproductive parasitism on the hybrid zone between two South African subspecies of honeybee, Apis mellifera capensis and A. m. scutellata. In my PhD project I will not only continue work on the role of reproductive parasitism in this hybrid zone, but also include Asian honeybees A. florea and A. cerana and Australian stingless bees.

Bee colonies are often portrayed as harmonious, xenophobic societies composed of workers that selflessly serve a queen who has total control over reproduction. Workers refrain from reproduction and thereby sacrifice their personal fitness in order to increase the reproductive output of the colony. However, opportunities for personal reproduction at the expense of colony-level fitness are often exploited by individual workers, a phenomenon known as worker reproductive parasitism (WRP). WRP has been observed in virtually all species of Apis. However, the effects on colony fitness, as well as the mechanisms by which WRP is controlled, have yet to be fully elucidated.

Previous work undertaken our lab has demonstrated that nest architecture and queen status are important factors affecting situations in which opportunities for WRP may arise. This project will seek to examine how bee colonies defend themselves from WRP by non-nestmates as well as from within.

Finally, I will also attempt to discover if WRP occurs in Australian stingless bees To date, almost nothing is known about the 15 or so species native to Australia. However, based on what is known about the dynamics of insect colonies, it is extremely unlikely that stingless bee colonies are free of WRP. I hope to reveal for the first time if WRP occurs, and if so, how it is regulated in Australian stingless bees.